This disclosure is generally directed to imaging, such as xerographic imaging and printing members, photoreceptors, photoconductors, and the like. More specifically, the present disclosure is directed to drum, multilayered drum, and flexible, belt imaging members, or devices comprised of a supporting medium like a substrate, a photogenerating layer, and a charge transport layer, including a plurality of charge transport layers, such as a first charge transport layer and a second charge transport layer, and wherein the photogenerating layer contains as an additive or dopant of a phosphonate and a photoconductor comprised of a supporting medium like a substrate, a phosphonate containing photogenerating layer, and a charge transport layer that results in photoconductors with a number of advantages, such as in embodiments, the minimization or substantial elimination of undesirable ghosting on developed images, such as xerographic images, including acceptable ghosting at various relative humidities; excellent cyclic and stable electrical properties; compatibility with the photogenerating and charge transport resin binders; and acceptable lateral charge migration (LCM) characteristics, such as for example, excellent LCM resistance. At least one in embodiments refers, for example, to one, from 1 to about 10, from 2 to about 6; from 2 to about 4; 2, and the like.
Ghosting refers, for example, to when a photoconductor is selectively exposed to positive charges in a number of xerographic print engines, some of the charges enter the photoconductor and manifest themselves as a latent image in the next printing cycle. This print defect can cause a change in the lightness of the half tones, and is commonly referred to as a “ghost” that is generated in the previous printing cycle. An example of a source of the positive charges is the stream of positive ions emitted from the transfer corotron. Since the paper sheets are situated between the transfer corotron and the photoconductor, the photoconductor is shielded from the positive ions from the paper sheets. In the areas between the paper sheets, the photoconductor is fully exposed, thus in this paper free zone the positive charges may enter the photoconductor. As a result, these charges cause a print defect or ghost in a half tone print if one switches to a larger paper format that covers the previous paper print free zone.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant such as pigment, charge additive, and surface additives, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the image to a suitable substrate, and permanently affixing the image thereto. In those environments wherein the device is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the imaging members and flexible belts disclosed herein can be selected for the Xerox Corporation iGEN3® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital, and/or color printing are thus encompassed by the present disclosure.
The photoconductors disclosed herein are in embodiments sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the photoconductors disclosed herein are in embodiments useful in high resolution color xerographic applications, particularly high-speed color copying and printing processes.